Conservative ministers have been ordered by Downing Street to stop making Government announcements that “distract” from the party’s core election messages.

Political strategists in Number 10 have issued an edict to Government departments effectively banning them from promoting initiatives that are not central to the party’s key election themes of crime, the economy, immigration and welfare.

The plan is understood to be the brainchild of the Tories’ election guru Lynton Crosby, who last year told David Cameron to “get the barnacles off the boat” in order to win in 2015. He wants to stop ministers “freelancing”, promoting themselves and their “pet projects” and confusing voters about what the Government stands for.

Policy areas likely to be affected by the new edict include announcements on international aid, the badger cull, and the Tory-backed Green Deal to improve energy efficiency.

But the move has irritated some Tory ministers, who claim it amounts to censorship by Downing Street and will allow the Liberal Democrats to take credit for the Government’s more socially liberal policies. The Liberal Democrats have made clear to their Conservative partners that their ministers will be free to speak out as they like.

Under a system set up by New Labour, and continued by the Coalition, all Government initiatives have to be cleared by Downing Street and put on a “grid” of announcements. The system is designed to allow the Prime Minister’s aides to co-ordinate Government activity and try to shape the media agenda by ensuring that important announcements don’t clash or appear contradictory.

Government sources said that over the last two weeks a significant number of announcements had been “culled” from the grid.

Ministers have been told that policy papers can still be published online, but they should not be promoted by departmental press offices or be accompanied by ministerial speeches. Controversially, the new policy is understood to also cover arms-length bodies such as the Environment Agency, which are supposed to be independent.

“Everyone has been told that ministers should only be making announcements that will help the party win the election in 2015,” said one Tory source. “That means talking about crime, immigration, welfare and the economy and not talking about foreign aid, the NHS or the Big Society. Most people understand where they’re coming from but a few ministers are feeling a bit put out that they’re effectively being told to shut up.”

A Government source added that Downing Street was increasingly frustrated by the number of small announcements coming from Whitehall departments on a weekly basis. “It’s about being disciplined and not trying to parade dozens of different policies all on the same day,” they said.

Several Government sources said they understood that Mr Crosby had initiated the move in response to his increasing frustration at “message indiscipline” within Government.

“Lynton has been telling them for months to make sure that everything coming out of Government reinforces the party’s core election message,” said one. “But so far it hasn’t worked.”

However Downing Street source played down the significance of the new edict.

“There are 365 days in the year and we are going to keep talking about all the issues where this Government is working hard to improve public services and build a sustainable recovery,” they said.